Firearm



Patented Aug. 4, 1931 UN-ITED STATES CHRIST'OPHER II. BIERBAUM, OF BUFFALQ'NEW YORK FIREARM Application fi1ed November 16, 1928. Seria1 N0. 319,752.

This invention relates t0 fire annsjand more particularly t0 tl1c barrel of the ame so as t0 i1nprove the accuracy of flight of the projectile as it leaves the muzzle of the barrel,

Heretofore the boxe of gun barrel shave becn riflecl so as to prduce therein grooves ancl lancls which alternatecl cir'cumferentially anal extenclecl unbrokcn to the outer encl 0f the muzzle.

angles t the axis of the sa'me or t 0 the axis of the bore of the barrel this inaccuracy 0f the base of the bullet will materially influence the accuracy of its fiight. This inaccuracy is clue co unbalancecl sicle pressure up jn the rear encl Portion 0f the bullet owing 130 the fact that the gas pressure of the muzzle blast starte; on the shorter sicle 0f the bi1llet before tl1is pressure acts 0n the longer sicle of.the

sa1ne, because the short sicle cf the bi1llet laves the niuzzle before the long sicle of the Same has clear ecl the b'arr-el. v It follows fro1n this uneven pressure against the sicles of the bullt at the rear encl of the samea lateral cleflectimi in the course 01": its projection occurs ancl this elfects inaccuracy in ics flight.

Not only. is such inaccurzlcy in the fl ight 0f' a bullet clue to defective arnmunition When manufacturecl, but such inaccuracy in the bul let is also produced as the same passes not be kept as true as though the bullkat were pushed through a sweclgihgclieby a Plunge1'n My invention therefore contemplates the provision 0f simple anclelficient means f0r improving the barrel ot" fire arms so as t0 secureaccuracy in the flight of thebullet issuing from the muzzleof the bore thereofl and to that encl the improvement consists in so organizing these means that' the blast 0f theezkhaust as it issuesfromthe muzzle Of the barrel Will be equalizecl arouncl tl1e en'tire circumfefence cf the projectile at the time lt iS cliScharged from the m uzzle ol:' the bai:rcl.

In the 'accompanying drawings: Fig. 1 is a front view oflshe In'uzzle ofthe When firing a projectile' 01 bullet the base of which is not at rightbarrel 0f a firearrn c onstructecl in accorclance with one form of my invention.

Figs. 2 and 3 are fragmentary longitudinal sections '0f the same, taken cn the corfesponclingly numberecl lines in Fig. l.

Fig. 4' is a cliagiammatic representatiori showing the bore Of' the bairel shown in Figs. 1,2 ancl 3 clevelopecl on a plane.

Figm 5 is a front'encl view of the firear1n bartel showing a modifiecl forrn of my invention.

Figs. 6 and 7 are fragmentary longitudinal sections 0f the san1e, tziken on lines 66 and 77 Fig. 5, respectively.

Fig 8 is a cliagrammatic view 0'f the structure shown' in Figs. 5, 6, ancl 7 clevel0pecl 0n a plane.

In the following clescription sim ilar characters 036 reference inclicace like arts in be several figures of the clrawings.

Referring t0 Ehe constructlon shown in Figs. l4 the numeral 10 iepresents the barrel cf a fircarm"which 1nay be eit her a rifie, cannon 01' the like aclaptecl t0 propl a bulletor projectile 11 with aflforward movement lengthwise cf its aXis ancl a rotary movemcnt arouncl the axis thereof.

The bore cf the bjarrels 0f such fireanns is usually proviclecl With l1elical groovs 12 ancl lancls 13 altcrnating cifcumferentially arouncl the 'surface of this bore whereby the bullet in ips forward passage through this bore unde1 the pressure 0f the gases rcslting from the ig1itecl charge cf powcler Will also be rotatecl about theaxis of the bullet ancl this Cii LIS

boxe clue to the elfdct cf the driving eclges 14 of the lands 13 whichlatter embecl themselves in theperiphery of the bullets 01 projectiles While through the barrel.

Inthe abs nce ofany Provision t0 prevent it any bullet 01 project ile having its rear encl 01' face 15 arrangeclat an oblique angle to heilig forcecl lengthwise 4. A firearm having its barrel provided with means for equalizing the exhaust blast on the base of a projectile by engaging the blast immediately with the side of the rear part of ehe projectile while the same lea.ves the muzz1e of the barre1.

5. A firearm having the bore 0f its barrel provided with means for rotating the projectile while projecting the same, .and also having means for equalizing the prssure of the exhaust blast upon the base of the proj ectile without rotative constraint of the same upon leaving the barrel and immediately engaging the blast with the side of the projectile adj acent to its base before the same leaves the barre1.

In testimony whereof I hereby affix my signature.

CHRISTOPHER H. BIERBAUM. 

